Differentiated tonsil-derived mesenchymal stem cells embedded in Matrigel restore parathyroid cell functions in rats with parathyroidectomy

Induced Pluripotent Stem Cell-Derived Parathyroid Organoids Resemble Parathyroid Morphology and Function

The primary role of the parathyroid glands is to maintain calcium homeostasis through the secretion of parathyroid hormone (PTH). The limited proliferative capacity and differentiation of parathyroid cells hinder the generation of cell therapy options. In this study, parathyroid organoids are successfully generated from human-induced pluripotent stem cells (hiPSCs). At the end of the 20 days of differentiation, the parathyroid organoids exhibited distinct parathyroid morphology. Stereomicroscope, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis demonstrated the 3D arrangement of the cell layers in which intracellular structures of parathyroid cells resemble human parathyroid cellular morphology. Comprehensive molecular analyses, including RNA sequencing (RNA-Seq) and liquid chromatography/mass spectrometry (LC-MS/MS), confirmed the expression of key parathyroid-related markers. Protein expression of CasR, CxCr4, Gcm2, and PTH are observed in parathyroid organoids. Parathyroid organoids secrete PTH, demonstrate active intercellular calcium signaling, and induce osteogenic differentiation via their secretome. The tissue integration potential of parathyroid organoids is determined by transplantation into parathyroidectomized rats. The organoid transplanted animals showed significant elevations in PTH-related markers (CasR, CxCr4, Foxn1, Gcm2, and PTH). PTH secretion is detected in organoid-transplanted animals. The findings represent a significant advancement in parathyroid organoid culture and may offer a cellular therapy for treating PTH-related diseases, including hypoparathyroidism.

Directed differentiation of human embryonic stem cells into parathyroid cells and establishment of parathyroid organoids

Differentiation of human embryonic stem cells (hESCs) into human embryonic stem cells-derived parathyroid-like cells (hESC-PT) has clinical significance in providing new therapies for congenital and acquired parathyroid insufficiency conditions. However, a highly reproducible, well-documented method for parathyroid differentiation remains unavailable. By imitating the natural process of parathyroid embryonic development, we proposed a new hypothesis about the in vitro differentiation of parathyroid-like cells. Transcriptome, differentiation marker protein detection and parathyroid hormone (PTH) secretion assays were performed after the completion of differentiation. To optimize the differentiation protocol and further improve the differentiation rate, we designed glial cells missing transcription factor 2 (GCM2) overexpression lentivirus transfection assays and constructed hESCs-derived parathyroid organoids. The new protocol enabled hESCs to differentiate into hESC-PT. HESC-PT cells expressed PTH, GCM2 and CaSR proteins, low extracellular calcium culture could stimulate hESC-PT cells to secrete PTH. hESC-PT cells overexpressing GCM2 protein secreted PTH earlier than their counterpart hESC-PT cells. Compared with the two-dimensional cell culture environment, hESCs-derived parathyroid organoids secreted more PTH. Both GCM2 lentiviral transfection and three-dimensional cultures could make hESC-PT cells functionally close to human parathyroid cells. Our study demonstrated that hESCs could differentiate into hESC-PT in vitro, which paves the road for applying the technology to treat hypoparathyroidism and introduces new approaches in the field of regenerative medicine.

Parathyroid-on-a-chip simulating parathyroid hormone secretion in response to calcium concentration

The parathyroid gland is an endocrine organ that plays a crucial role in regulating calcium levels in blood serum through the secretion of parathyroid hormone (PTH). Hypoparathyroidism is a chronic disease that can occur due to parathyroid defects, but due to the difficulty of creating animal models of this disease or obtaining human normal parathyroid cells, the evaluation of parathyroid functionality for drug development is limited. Although parathyroid-like cells that secrete PTH have recently been reported, their functionality may be overestimated using traditional culture methods that lack in vivo similarities, particularly vascularization. To overcome these limitations, we obtained parathyroid organoids from tonsil-derived mesenchymal stem cells (TMSCs) and fabricated a parathyroid-on-a-chip, capable of simulating PTH secretion based on calcium concentration. This chip exhibited differences in PTH secretion according to calcium concentration and secreted PTH within the range of normal serum levels. In addition, branches of organoids, which are difficult to observe in animal models, were observed in this chip. This could serve as a guideline for successful engraftment in implantation therapies in the future.

Effects of an Adipose Mesenchymal Stem Cell-Derived Conditioned medium and TGF-β1 on Human Keratinocytes In Vitro

Human keratinocytes play a crucial role during skin wound healing and in skin replacement therapies. The secretome of adipose-derived stem cells (ASCs) has been shown to secrete pro-healing factors, among which include TGF-β1, which is essential for keratinocyte migration and the re-epithelialization of cutaneous wounds during skin wound healing. The benefits of an ASC conditioned medium (ASC-CM) are primarily orchestrated by trophic factors that mediate autocrine and paracrine effects in keratinocytes. Here, we evaluated the composition and the innate characteristics of the ASC secretome and its biological effects on keratinocyte maturation and wound healing in vitro. In particular, we detected high levels of different growth factors, such as HGF, FGFb, and VEGF, and other factors, such as TIMP1 and 4, IL8, PAI-1, uPA, and IGFBP-3, in the ASC-CM. Further, we investigated, using immunofluorescence and flow cytometry, the distinct effects of a human ASC-CM and/or synthetic TGF-β1 on human keratinocyte proliferation, migration, and cell apoptosis suppression. We demonstrated that the ASC-CM increased keratinocyte proliferation as compared to TGF-β1 treatment. Further, we found that the ASC-CM exerted cell cycle progression in keratinocytes via regulating the phases G1, S, and G2/M. In particular, cells subjected to the ASC-CM demonstrated increased DNA synthesis (S phase) compared to the TGF-β1-treated KCs, which showed a pronounced G0/G1 phase. Furthermore, both the ASC-CM and TGF-β1 conditions resulted in a decreased expression of the late differentiation marker CK10 in human keratinocytes in vitro, whereas both treatments enhanced transglutaminase 3 and loricrin expression. Interestingly, the ASC-CM promoted significantly increased numbers of keratinocytes expressing epidermal basal keratinocyte markers, such DLL1 and Jagged2 Notch ligands, whereas those ligands were significantly decreased in TGF-β1-treated keratinocytes. In conclusion, our findings suggest that the ASC-CM is a potent stimulator of human keratinocyte proliferation in vitro, particularly supporting basal keratinocytes, which are crucial for a successful skin coverage after transplantation. In contrast, TGF-β1 treatment decreased keratinocyte proliferation and specifically increased the expression of differentiation markers in vitro.

New Sources, Differentiation, and Therapeutic Uses of Mesenchymal Stem Cells 2.0

For the clinical application of mesenchymal stem cells (MSCs), the optimization of biological products (e [...].

Patient-derived parathyroid organoids as a tracer and drug-screening application model

Parathyroid diseases are characterized by dysregulation of calcium homeostasis and alterations in parathyroid hormone (PTH) excretion. The development of parathyroid-targeted treatment and imaging tracers could benefit from in vitro models. Therefore, we aim to establish a patient-derived parathyroid organoid model representing human parathyroid tissue. Hyperplastic parathyroid tissue was dispersed, and parathyroid organoids (PTOs) were cultured and characterized. PTO-derived cells exhibited self-renewal over several passages, indicative of the presence of putative stem cells. Immunofluorescence and RNA sequencing confirmed that PTOs phenocopy hyperplastic parathyroid tissue. Exposure of PTOs to increasing calcium concentrations and PTH-lowering drugs resulted in significantly reduced PTH excretion. PTOs showed specific binding of the imaging tracers ¹¹C-methionine and ^99mTc-sestamibi. These data show the functionality of PTOs resembling the parathyroid. This PTO model recapitulates the originating tissue on gene and protein expression and functionality, paving the way for future physiology studies and therapeutic target and tracer discovery.

Parathyroid Cell Differentiation from Progenitor Cells and Stem Cells: Development, Molecular Mechanism, Function, and Tissue Engineering

Parathyroid glands are endocrine organs which are located posterior to thyroid glands and control secretion of parathyroid hormone (PTH) in order to regulate blood calcium level. PTH maintains calcium homeostasis by acting on the bone, kidney, and small intestine. PTH deficiency leads to chronic hypocalcemia, organ calcinosis, kidney and heart failure, painful muscle spasms, neuromuscular problems, and memory problems. Since parathyroid cells have inadequate proliferation potential in culture conditions, their utilization as a cellular therapy option is very limited. Although studies conducted so far include parathyroid cell differentiation from various cell types, problems related to successful cellular differentiation and transplantation still remain. Recently, parathyroid tissue engineering has attracted attention as a potential treatment for the parathyroid-related diseases caused by hypoparathyroidism. Although major progression is made in the construction of tissue engineering protocols using parathyroid cells and biomaterials, PTH secretion to mimic its spontaneous harmony in the body is a challenge. This chapter comprehensively defines the derivation of parathyroid cells from various cell sources including pluripotent stem cells, molecular mechanisms, and tissue engineering applications.

Advances in 3D bioprinting of tissues/organs for regenerative medicine and in-vitro models

Tissue/organ shortage is a major medical challenge due to donor scarcity and patient immune rejections. Furthermore, it is difficult to predict or mimic the human disease condition in animal models during preclinical studies because disease phenotype differs between humans and animals. Three-dimensional bioprinting (3DBP) is evolving into an unparalleled multidisciplinary technology for engineering three-dimensional (3D) biological tissue with complex architecture and composition. The technology has emerged as a key driver by precise deposition and assembly of biomaterials with patient's/donor cells. This advancement has aided in the successful fabrication of in vitro models, preclinical implants, and tissue/organs-like structures. Here, we critically reviewed the current state of 3D-bioprinting strategies for regenerative therapy in eight organ systems, including nervous, cardiovascular, skeletal, integumentary, endocrine and exocrine, gastrointestinal, respiratory, and urinary systems. We also focus on the application of 3D bioprinting to fabricated in vitro models to study cancer, infection, drug testing, and safety assessment. The concept of in situ 3D bioprinting is discussed, which is the direct printing of tissues at the injury or defect site for reparative and regenerative therapy. Finally, issues such as scalability, immune response, and regulatory approval are discussed, as well as recently developed tools and technologies such as four-dimensional and convergence bioprinting. In addition, information about clinical trials using 3D printing has been included.

Development of Surgically Transplantable Parathyroid Hormone-Releasing Microbeads

Hypoparathyroidism is an endocrine disorder that occurs because of the inability to produce parathyroid hormone (PTH) effectively. Previously, we reported the efficacy of tonsil-derived mesenchymal stem cells (TMSCs) differentiated into parathyroid-like cells for the treatment of hypoparathyroidism. Here, we investigated the feasibility of three-dimensional structural microbeads fabricated with TMSCs and alginate, a natural biodegradable polymer, to treat hypoparathyroidism. Alginate microbeads were fabricated by dropping a 2% (w/v) alginate solution containing TMSCs into a 5% CaCl2 solution and then differentiated into parathyroid-like cells using activin A and sonic hedgehog for 7 days. The protein expression of PTH, a specific marker of the parathyroid gland, was significantly higher in differentiated alginate microbeads with TMSCs (Al-dT) compared with in undifferentiated alginate microbeads with TMSCs. For in vivo experiments, we created the hypoparathyroidism animal model by parathyroidectomy (PTX) and implanted alginate microbeads in the dorsal interscapular region. The PTX rats with Al-dT (PTX+Al-dT) showed the highest survival rate and weight change and a gradual increase in serum intact PTH levels. We also detected a higher expression of PTH in retrieved tissues of PTX+Al-dT using immunofluorescence analysis. This study demonstrates that alginate microbeads are potential a new tool as a surgically scalable therapy for treating hypoparathyroidism.

Density-Dependent Differentiation of Tonsil-Derived Mesenchymal Stem Cells into Parathyroid-Hormone-Releasing Cells

Mesenchymal stem cells (MSCs) can differentiate into endoderm lineages, especially parathyroid-hormone (PTH)-releasing cells. We have previously reported that tonsil-derived MSC (T-MSC) can differentiate into PTH-releasing cells (T-MSC-PTHCs), which restored the parathyroid functions in parathyroidectomy (PTX) rats. In this study, we demonstrate quality optimization by standardizing the differentiation rate for a better clinical application of T-MSC-PTHCs to overcome donor-dependent variation of T-MSCs. Quantitation results of PTH mRNA copy number in the differentiated cells and the PTH concentration in the conditioned medium confirmed that the differentiation efficiency largely varied depending on the cells from each donor. In addition, the differentiation rate of the cells from all the donors greatly improved when differentiation was started at a high cell density (100% confluence). The large-scale expression profiling of T-MSC-PTHCs by RNA sequencing indicated that those genes involved in exiting the differentiation and the cell cycle were the major pathways for the differentiation of T-MSC-PTHCs. Furthermore, the implantation of the T-MSC-PTHCs, which were differentiated at a high cell density embedded in hyaluronic acid, resulted in a higher serum PTH in the PTX model. This standardized efficiency of differentiation into PTHC was achieved by initiating differentiation at a high cell density. Our findings provide a potential solution to overcome the limitations due to donor-dependent variation by establishing a standardized differentiation protocol for the clinical application of T-MSC therapy in treating hypoparathyroidism.

The promising rise of bioprinting in revolutionalizing medical science: Advances and possibilities

Bioprinting is a relatively new yet evolving technique predominantly used in regenerative medicine and tissue engineering. 3D bioprinting techniques combine the advantages of creating Extracellular Matrix (ECM)like environments for cells and computer-aided tailoring of predetermined tissue shapes and structures. The essential application of bioprinting is for the regeneration or restoration of damaged and injured tissues by producing implantable tissues and organs. The capability of bioprinting is yet to be fully scrutinized in sectors like the patient-specific spatial distribution of cells, bio-robotics, etc. In this review, currently developed experimental systems and strategies for the bioprinting of different types of tissues as well as for drug delivery and cancer research are explored for potential applications. This review also digs into the most recent opportunities and future possibilities for the efficient implementation of bioprinting to restructure medical and technological practices.

Hypoparathyroidism: State of the Art on Cell and Tissue Therapies

Hypoparathyroidism is an endocrine disorder characterized by low serum calcium levels, high serum phosphorus levels, and by inappropriate or absent secretion of the parathyroid hormone (PTH). The most common therapeutic strategy to treat this condition is hormone replacement therapy with calcium and vitamin D but, unfortunately, in the long term this treatment may not be sufficient to compensate for the loss of endocrine function. Glandular autotransplantation is considered the most effective technique in place of replacement therapy. Although it leads to excellent results in most cases, autotransplantation is not always possible. Allograft is a good way to treat patients who have not been able to undergo autograft, but this technique has limited success due to side effects related to tissue rejection. This therapy is supported by systemic immunosuppression, which leads to the onset of serious side effects in patients, with a risk of endocrine toxicity. Today, research on endocrine disorders is focused on discovering alternative graft therapies that can allow optimal results with the fewest possible side effects. In this review, we will make an update on the current state of the art about the cell and tissue therapy as treatment for hypoparathyroidism, to identify which type of therapeutic strategy could be valid for a future clinical use.

Octanoyl glycol chitosan enhances the proliferation and differentiation of tonsil-derived mesenchymal stem cells

Biofunctional polymers have been widely used to enhance the proliferation and functionality of stem cells. Here, we report the development of a new biofunctional polymer, octanoyl glycol chitosan (OGC), and demonstrate its effects on the cell cycle and stem cell function using tonsil-derived mesenchymal stem cells (TMSCs). OGC treatment (100 μg/mL) significantly increased the proliferation of TMSCs, which could be attributed to cyclin D1 up-regulation in the G1 phase of the cell cycle. Additionally, OGC enhanced the ability of TMSCs to differentiate into adipocytes, chondrocytes, and osteoblasts. Taken together, this new biofunctional polymer, OGC, can promote stemness and osteogenesis, as well as induce stem cell proliferation by enhancing the intracellular metabolic rate and regulating the cell cycle. Thus, in the future, OGC could be a potential therapeutic additive for improving stem cell function.

Therapeutic Effect of IL1β Priming Tonsil Derived-Mesenchymal Stem Cells in Osteoporosis

BACKGROUND

Stem cell therapies can be a new therapeutic strategy that may rebalance anabolic and anti-resorptive effects in osteoporosis patients. Tonsil-derived mesenchymal stem cells (TMSCs) can be an alternative therapeutic source for chronic degenerative diseases including osteoporosis. MSCs acquire immune regulatory function under the inflammatory cytokines. Since interleukin (IL) 1β is known to be one of inflammatory cytokines involved in osteoporosis progression, treatment of IL1β with TMSCs may enhance immunomodulatory function and therapeutic effects of TMSCs in osteoporosis.

METHODS

For IL1β priming, TMSCs were cultured in the presence of the medium containing IL1β for 1 day. Characteristics of IL1β priming TMSCs such as multipotent differentiation properties, anti-inflammatory potential, and suppression of osteoclast differentiation were assessed in vitro. For in vivo efficacy study, IL1β priming TMSCs were intravenously infused twice with ovariectomized (OVX) osteoporosis mouse model, and blood serum and bone parameters from micro computed tomography images were analyzed.

RESULTS

IL1β priming TMSCs had an enhanced osteogenic differentiation and secreted factors that regulate both osteoclastogenesis and osteoblastogenesis. IL1β priming TMSCs also suppressed proliferation of peripheral blood mononuclear cells (PBMCs) and decreased expression of Receptor activator of nuclear factor kappa-Β ligand (RANKL) in PHA-stimulated PBMCs. Furthermore, osteoclast specific genes such as Nuclear factor of activated T cells c1 (NFATc1) were effectively down regulated when co-cultured with IL1β priming TMSCs in RANKL induced osteoclasts. In OVX mice, IL1β priming TMSCs induced low level of serum RANKL/osteoprotegerin (OPG) ratio on the first day of the last administration. Four weeks after the last administration, bone mineral density and serum Gla-osteocalcin were increased in IL1β priming TMSC-treated OVX mice. Furthermore, bone formation and bone resorption markers that had been decreased in OVX mice with low calcium diet were recovered by infusion of IL1β priming TMSCs.

CONCLUSION

IL1β priming can endow constant therapeutic efficacy with TMSCs, which may contribute to improve bone density and maintain bone homeostasis in postmenopausal osteoporosis. Therefore, IL1β priming TMSCs can be a new therapeutic option for treating postmenopausal osteoporosis.

Adipose derived stem cells to construct parathyroid organoid for hypoparathyroidism

Hypoparathyroidism is one of the most common postoperative complications of thyroid surgery, and organoid transplantation is a frontier field expected to treat hypoparathyroidism. Organoids are three-dimensional cell aggregates derived from embryonic stem cells, pluripotent stem cells, or tissue precursor cells, possessing similar structures and functions to organs. Thus they can replace diseased organs to play a role. Adipose-derived stem cells (ASCs) are a population of postnatal stem cells residing in the fat tissue, capable of differentiating into parathyroid-like cells with parathyroid hormone secretion function. Additionally, we have prepared cartilaginous organoids by intelligent porous hydrogel and differentiated ASCs via "bottom-up" strategy in vitro. Therefore, we speculate that parathyroid organoids can be achieved by the biomaterial-assisted assembly of differentiated adipose stem cells and it is a promising treatment for hypoparathyroidism.

A Novel Method to Differentiate Tonsil-Derived Mesenchymal Stem Cells In Vitro into Estrogen-Secreting Cells

BACKGROUND

The advantages of tonsil-derived mesenchymal stem cells (TMSCs) over other mesenchymal stem cells (MSCs) include higher proliferation rates, various differentiation potentials, efficient immune-modulating capacity, and ease of obtainment. Specifically, TMSCs have been shown to differentiate into the endodermal lineage. Estrogen deficiency is a major cause of postmenopausal osteoporosis and is associated with higher incidences of ischemic heart disease and cerebrovascular attacks during the postmenopausal period. Therefore, stem cell-derived, estrogen-secreting cells might be used for estrogen deficiency.

METHODS

Here, we developed a novel method that utilizes retinoic acid, insulin-like growth factor-1, basic fibroblast growth factor, and dexamethasone to evaluate the differentiating potential of TMSCs into estrogen-secreting cells. The efficacy of the novel differentiating method for generation of estrogen-secreting cells was also evaluated with bone marrow- and adipose tissue-derived MSCs.

RESULTS

Incubating TMSCs in differentiating media induced the gene expression of cytochrome P450 19A1 (CYP19A1), which plays a key role in estrogen biosynthesis, and increased 17β-estradiol secretion upon testosterone addition. Furthermore, CYP11A1, CYP17A1, and 3β-hydroxysteroid dehydrogenase type-1 gene expression levels were significantly increased in TMSCs. In bone marrow-derived and adipose tissue-derived MSCs, this differentiation method also induced the gene expression of CYP19A1, but not CYP17A1, suggesting TMSCs are a superior source for estrogen secretion.

CONCLUSION

These results imply that TMSCs can differentiate into functional estrogen-secreting cells, thus providing a novel, alternative cell therapy for estrogen deficiency.

A transcriptomic analysis of serial-cultured, tonsil-derived mesenchymal stem cells reveals decreased integrin α3 protein as a potential biomarker of senescent cells

BACKGROUND

Mesenchymal stem cells (MSCs) have been widely used for stem cell therapy, and serial passage of stem cells is often required to obtain sufficient cell numbers for practical applications in regenerative medicine. A long-term serial cell expansion can potentially induce replicative senescence, which leads to a progressive decline in stem cell function and stemness, losing multipotent characteristics. To improve the therapeutic efficiency of stem cell therapy, it would be important to identify specific biomarkers for senescent cells.

METHODS

Tonsil-derived mesenchymal stem cells (TMSCs) with 20-25 passages were designated as culture-aged TMSCs, and their mesodermal differentiation potentials as well as markers of senescence and stemness were compared with the control TMSCs passaged up to 8 times at the most (designated as young). A whole-genome analysis was used to identify novel regulatory factors that distinguish between the culture-aged and control TMSCs. The identified markers of replicative senescence were validated using Western blot analyses.

RESULTS

The culture-aged TMSCs showed longer doubling time compared to control TMSCs and had higher expression of senescence-associated (SA)-β-gal staining but lower expression of the stemness protein markers, including Nanog, Oct4, and Sox2 with decreased adipogenic, osteogenic, and chondrogenic differentiation potentials. Microarray analyses identified a total of 18,614 differentially expressed genes between the culture-aged and control TMSCs. The differentially expressed genes were classified into the Gene Ontology categories of cellular component (CC), functional component (FC), and biological process (BP) using KEGG (Kyoto encyclopedia of genes and genomes) pathway analysis. This analysis revealed that those genes associated with CC and BP showed the most significant difference between the culture-aged and control TMSCs. The genes related to extracellular matrix-receptor interactions were also shown to be significantly different (p < 0.001). We also found that culture-aged TMSCs had decreased expressions of integrin α3 (ITGA3) and phosphorylated AKT protein (p-AKT-Ser473) compared to the control TMSCs.

CONCLUSIONS

Our data suggest that activation of ECM-receptor signaling, specifically involved with integrin family-mediated activation of the intracellular cell survival-signaling molecule AKT, can regulate stem cell senescence in TMSCs. Among these identified factors, ITGA3 was found to be a representative biomarker of the senescent TMSCs. Exclusion of the TMSCs with the senescent TMSC markers in this study could potentially increase the therapeutic efficacy of TMSCs in clinical applications.

Tissue-engineered parathyroid gland and its regulatory secretion of parathyroid hormone

Parathyroid glands (PTGs) are important endocrine organs being mainly responsible for the secretion of parathyroid hormone (PTH) to regulate the balance of calcium (Ca) /phosphorus (P) ions in the body. Once PTGs get injured or removed, their resulting defect or loss of PTH secretion should disturb the level of Ca/P in blood, thus damaging other related organs (bone, kidney, etc.) and even causing death. Recently, tissue-engineered PTGs (TE-PTGs) have attracted lots of attention as a potential treatment for the related diseases of PTGs caused by hypoparathyroidism and hyperparathyroidism, including tetany, muscle cramp, nephrolithiasis, nephrocalcinosis, and osteoporosis. Although great progress has been made in the establishment of TE-PTGs with an effective strategy to integrate the key factors of cells and biomaterials, its regulatory secretion of PTH to mimic its natural rhythms in the body remains a huge challenge. This review comprehensively describes an overview of PTGs from physiology and pathology to cytobiology and tissue engineering. The state of the arts in TE-PTGs and the feasible strategies to regulate PTH secretion behaviors are highlighted to provide an important foundation for further investigation.

Optimization of tenocyte lineage-related factors from tonsil-derived mesenchymal stem cells using response surface methodology

BACKGROUND

In order to optimize the tenogenic differentiation of mesenchymal stem cells (MSCs), researchers should consider various factors. However, this requires testing numerous experimental settings, which is costly and time-consuming. We aimed to assess the differential effects of transforming growth factor beta-3 (TGF-β3) on the tenogenesis of tonsil-derived MSCs (T-MSCs) and bone marrow-derived MSCs (BM-MSCs) using response surface methodology (RSM).

METHODS

Bone marrow and tonsillar tissue were collected from four patients; mononuclear cells were separated and treated with 5 or 10 ng/mL of TGF-β3. A full factorial experimental design with a categorical factor of 0 was employed to study the effect of tension based on T-MSCs. Eighty-four trials were fitted with RSM and then used to obtain mathematical prediction models.

RESULTS

Exposure of T-MSCs and BM-MSCs to TGF-β3 increased the expression of scleraxis (SCX), tenomodulin (TNMD), decorin, collagen I, and tenascin C. Expression of most of these factors reached a maximum after 2-3 days of treatment. The model predicted that the values of the tenocyte lineage-related factors assessed would be significantly increased at 2.5 days of culture with 2.7 ng/mL of TGF-β3 for T-MSCs and at 2.3 days of culture regardless of TGF-β3 concentration for BM-MSCs.

CONCLUSIONS

This study demonstrated that the RSM prediction of the culture time necessary for the tenogenic differentiation of T-MSCs and BM-MSCs under TGF-β3 stimulation was similar to the experimentally determined time of peak expression of tenocyte-related mRNAs, suggesting the potential of using the RSM approach for optimization of the culture protocol for tenogenesis of MSCs.

Differentiation of Rat Adipose-Derived Stem Cells into Parathyroid-Like Cells

BACKGROUND

The current treatment for postoperative hypoparathyroidism has shortcomings, such as repeated blood monitoring for dosage adjustment, uncertain long-term efficacy, and the high price of recombinant parathyroid hormone therapy. Adipose-derived stem cells can undergo adipogenic and osteogenic differentiation in vitro and are considered a novel source of parathyroid-like cells, but the idea lacks theoretical basis and feasibility. We aimed at establishing a protocol for differentiating adipose-derived stem cells into parathyroid-like cells for treating hypoparathyroidism.

MATERIALS

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METHODS

Adipose-derived stem cells were isolated and purified from the inguinal adipose tissue of Sprague Dawley rats. Adipogenic differentiation and osteogenic differentiation of the cells were identified by oil red O and alizarin red S staining, respectively. The adipose-derived stem cells were stimulated by sonic hedgehog (SHH) and activin A. The differentiation of the adipose-derived stem cells to parathyroid-like cells was confirmed by the detection of parathyroid hormone and the related parathyroid markers.

RESULTS

Adipose-derived stem cells were successfully isolated and purified from the rat adipocytes. The adipogenic and osteogenic differentiation capabilities of the adipose-derived stem cells were determined. SHH and activin A stimulated parathyroid hormone secretion by the adipose-derived stem cells and significantly increased the expression of calcium-sensing receptor (CaSR), parathyroid hormone, and glial cells missing homolog 2 (GCM2) in the cells in a time- and concentration-dependent manner.

CONCLUSION

We successfully differentiated rat adipose-derived stem cells into parathyroid-like cells, which will pave a new route to curing hypoparathyroidism.

Optimization of Microenvironments Inducing Differentiation of Tonsil-Derived Mesenchymal Stem Cells into Endothelial Cell-Like Cells

BACKGROUND

Stem cell engineering is appealing consideration for regenerating damaged endothelial cells (ECs) because stem cells can differentiate into EC-like cells. In this study, we demonstrate that tonsil-derived mesenchymal stem cells (TMSCs) can differentiate into EC-like cells under optimal physiochemical microenvironments.

METHODS

TMSCs were preconditioned with Dulbecco's Modified Eagle Medium (DMEM) or EC growth medium (EGM) for 4 days and then replating them on Matrigel to observe the formation of a capillary-like network under light microscope. Microarray, quantitative real time polymerase chain reaction, Western blotting and immunofluorescence analyses were used to evaluate the expression of gene and protein of EC-related markers.

RESULTS

Preconditioning TMSCs in EGM for 4 days and then replating them on Matrigel induced the formation of a capillary-like network in 3 h, but TMSCs preconditioned with DMEM did not form such a network. Genome analyses confirmed that EGM preconditioning significantly affected the expression of genes related to angiogenesis, blood vessel morphogenesis and development, and vascular development. Western blot analyses revealed that EGM preconditioning with gelatin coating induced the expression of endothelial nitric oxide synthase (eNOS), a mature EC-specific marker, as well as phosphorylated Akt at serine 473, a signaling molecule related to eNOS activation. Gelatin-coating during EGM preconditioning further enhanced the stability of the capillary-like network, and also resulted in the network more closely resembled to those observed in human umbilical vein endothelial cells.

CONCLUSION

This study suggests that under specific conditions, i.e., EGM preconditioning with gelatin coating for 4 days followed by Matrigel, TMSCs could be a source of generating endothelial cells for treating vascular dysfunction.

Tonsil-derived stem cells as a new source of adult stem cells

Located near the oropharynx, the tonsils are the primary mucosal immune organ. Tonsil tissue is a promising alternative source for the high-yield isolation of adult stem cells, and recent studies have reported the identification and isolation of tonsil-derived stem cells (T-SCs) from waste surgical tissue following tonsillectomies in relatively young donors (i.e., under 10 years old). As such, T-SCs offer several advantages, including superior proliferation and a shorter doubling time compared to bone marrow-derived mesenchymal stem cells (MSCs). T-SCs also exhibit multi-lineage differentiation, including mesodermal, endodermal (e.g., hepatocytes and parathyroid-like cells), and even ectodermal cells (e.g., Schwann cells). To this end, numbers of researchers have evaluated the practical use of T-SCs as an alternative source of autologous or allogenic MSCs. In this review, we summarize the details of T-SC isolation and identification and provide an overview of their application in cell therapy and regenerative medicine.

Application of Tonsil-Derived Mesenchymal Stem Cells in Tissue Regeneration: Concise Review

Since the discovery of stem cells and multipotency characteristics of mesenchymal stem cells (MSCs), there has been tremendous development in regenerative medicine. MSCs derived from bone marrow have been widely used in various research applications, yet there are limitations such as invasiveness of obtaining samples, low yield and proliferation rate, and questions regarding their practicality in clinical applications. Some have suggested that MSCs from other sources, specifically those derived from palatine tonsil tissues, that is, tonsil‐derived MSCs (TMSCs), could be considered as a new potential therapeutic tool in regenerative medicine due to their superior proliferation rate and differentiation capabilities with low immunogenicity and ease of obtaining. Several studies have determined that TMSCs have differentiation potential not only into the mesodermal lineage but also into the endodermal as well as ectodermal lineages, expanding their potential usage and placing them as an appealing option to consider for future studies in regenerative medicine. In this review, the differentiation capacities of TMSCs and their therapeutic competencies from past studies are addressed. stem cells2019;37:1252–1260

Administration of Tonsil-Derived Mesenchymal Stem Cells Improves Glucose Tolerance in High Fat Diet-Induced Diabetic Mice via Insulin-Like Growth Factor-Binding Protein 5-Mediated Endoplasmic Reticulum Stress Modulation

Type 2 diabetes mellitus (T2DM) is a prevalent chronic metabolic disorder accompanied by high blood glucose, insulin resistance, and relative insulin deficiency. Endoplasmic reticulum (ER) stress induced by high glucose and free fatty acids has been suggested as one of the main causes of β-cell dysfunction and death in T2DM. Stem cell-derived insulin-secreting cells were recently suggested as a novel therapy for diabetes. In the present study, we demonstrate the therapeutic potential of tonsil-derived mesenchymal stem cells (TMSCs) to treat high-fat diet (HFD)-induced T2DM. To explore whether TMSC administration can alleviate T2DM, TMSCs were intraperitoneally injected in HFD-induced T2DM mice once every 2 weeks. TMSC injection markedly improved glucose tolerance and glucose-stimulated insulin secretion and prevented HFD-induced pancreatic β-cell hypertrophy and cell death. In addition, TMSC injection relieved the ER-stress response and preserved gene expression related to glucose sensing and insulin secretion. Moreover, administration of TMSC-derived conditioned medium induced similar therapeutic outcomes, suggesting paracrine effects. Finally, proteomic analysis revealed high secretion of insulin-like growth factor-binding protein 5 by TMSCs, and its expression was critical for the protective effects of TMSCs against HFD-induced glucose intolerance and ER-stress response in pancreatic islets. TMSC administration can alleviate HFD-induced-T2DM via preserving pancreatic islets and their function. These results provide novel evidence of TMSCs as an ER-stress modulator that may be a novel, alternative cell therapy for T2DM.

A 3D-printed polycaprolactone/β-tricalcium phosphate mandibular prosthesis: A pilot animal study

OBJECTIVE

In this study, we assessed the effectiveness of a tonsil-derived mesenchymal stem cell (TMSC)-transplanted polycaprolactone/beta-tricalcium phosphate prosthesis (specifically designed for easier fixing and grafting with a single scaffold) on rabbit mandible osteogenesis.

METHODS

The mandibles of 18 rabbits were exposed, and 10 × 8-mm bone defects were made. Two rabbits did not receive implants; four were reconstructed with the scaffold control (SC) (SC group); four were reconstructed with scaffolds soaked in peripheral blood (PB) (PB group); four were reconstructed with TMSC-transplanted scaffolds (TMSC group); and four were reconstructed with differentiated osteocyte-transplanted scaffolds (DOC) (DOC group). Each rabbit was sacrificed 12 weeks after surgery, and the area of new bone formation was investigated by mechanical testing, histology, and micro-computed tomography.

RESULTS

More extended and denser new bone masses were observed in the TMSC and DOC groups, although fibrosis and vascular formation levels were similar in all groups, suggesting that the dual-structured scaffold alone provides a good environment for bone attachment and regeneration. The bone volumes of representative scaffolds from the SC, PB, TMSC, and DOC groups were 43.12, 48.35, 53.10, and 57.44% of the total volumes, respectively.

CONCLUSION

The design of the scaffold resulted in effective osteogenesis, and TMSCs showed osteogenic potency, indicating that their combination could enable effective bone regeneration.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:358-366, 2020.

Polypeptide Thermogels as Three-Dimensional Scaffolds for Cells

BACKGROUND

Thermogel is an aqueous solution that exhibits a sol-to-gel transition as the temperature increases. Stem cells, growth factors, and differentiating factors can be incorporated in situ in the matrix during the sol-to-gel transition, leading to the formation of a three-dimensional (3D) cell-culture scaffold.

METHODS

The uses of thermogelling polypeptides, such as collagen, Matrigel™, elastin-like polypeptides, and synthetic polypeptides, as 3D scaffolds of cells, are summarized in this paper.

RESULTS

The timely supply of growth factors to the cells, cell survival, and metabolite removal is to be insured in the cell culture matrix. Various growth factors were incorporated in the matrix during the sol-to-gel transition of the thermogelling polypeptide aqueous solutions, and preferential differentiation of the incorporated stem cells into specific target cells were investigated. In addition, modulus of the matrix was controlled by post-crosslinking reactions of thermogels or employing composite systems. Chemical functional groups as well as biological factors were selected appropriately for targeted differentiation of the incorporated stem cells.

CONCLUSION

In addition to all the advantages of thermogels including mild conditions for cell-incorporation and controlled supplies of the growth factors, polypeptide thermogels provide neutral pH environments to the cells during the degradation of the gel. Polypeptide thermogels as an injectable scaffold can be a promising system for their eventual in vivo applications in stem cell therapy.

Feasibility of autologous plasma gel for tonsil-derived stem cell therapeutics in hypoparathyroidism

Hypoparathyroidism is a deficiency of the parathyroid hormone (PTH) in the body. We previously reported the possibility of treating it using tonsil-derived mesenchymal stem cells (TMSCs) differentiated into PTH-releasing cells. The purpose of this study was to evaluate the feasibility of using autologous plasma gel as scaffold material in treatment of hypoparathyroidism with TMSC. We obtained plasma by venous sampling of autologous blood and centrifuged and fabricated the plasma gel using a sinusoidal pattern heating machine. After we created the hypoparathyroidism animal model, we administered undifferentiated TMSCs and TMSCs differentiated into parathyroid cells at each rat dorsum by intramuscular injection with and without the plasma gel. In the plasma gel groups, intact PTH was detected from on day 21 after TMSC injection; we did not detect intact PTH in the groups that were only transplanted with TMSCs during the entire experimental period. Serum calcium was higher and phosphorous was lower in the TMSC with plasma gel groups than in the groups with TMSCs alone. We detected PTH and chromogranin A in the TMSC-plasma gel-transplanted areas on immunohistochemistry and immunofluorescence stain. Plasma gel can be considered as a cell-delivery scaffold for treating hypoparathyroidism with tonsil-derived mesenchymal stem cells.

Double intratibial injection of human tonsil-derived mesenchymal stromal cells recovers postmenopausal osteoporotic bone mass

BACKGROUND AND AIMS

Osteoporosis, which is a disease characterized by weakening of the bone, affects a large portion of the senior population. The current therapeutic options for osteoporosis have side effects, and there is no effective treatment for severe osteoporosis. Thus, we urgently need new treatment strategies, such as topical therapies and/or safe and effective stem cell therapies.

METHODS

We investigated the therapeutic potential of directly injecting human tonsil-derived mesenchymal stem cells (TMSC) into the right proximal tibias of ovariectomized postmenopausal osteoporosis model mice. Injections were given once (1×) or twice (2×) during the 3-month experimental period. At the end of the experiment, micro-computed tomographic images revealed some improvement in the proximal tibias and more significant improvement in the femoral heads of treated mice.

RESULTS

Osteogenic effect was qualitatively and quantitatively more pronounced in TMSC/2×-treated mice. Furthermore, TMSC/2× mice exhibited significant recovery of the serum osteocalcin level, which is pathologically elevated in osteoporosis, and increased serum alkaline phosphatase, which indicates bone formation. TMSC therapy was generally well tolerated and caused no apparent toxicity in the experimental mice. Moreover, TMSC therapy reduced visceral fat.

CONCLUSION

Our results demonstrate that double injection of TMSC directly into the proximal tibia triggers recovery of osteoporosis, and thus could be a potential therapeutic approach for severe bone loss.

Tonsil-derived mesenchymal stem cell-embedded in situ crosslinkable gelatin hydrogel therapy recovers postmenopausal osteoporosis through bone regeneration

We investigated therapeutic potential of human tonsil-derived mesenchymal stem cells (TMSC) subcutaneously delivered to ovariectomized (OVX) mice for developing more safe and effective therapy for osteoporosis. TMSC were isolated from tonsil tissues of children undergoing tonsillectomy, and TMSC-embedded in situ crosslinkable gelatin-hydroxyphenyl propionic acid hydrogel (TMSC-GHH) or TMSC alone were delivered subcutaneously to the dorsa of OVX mice. After 3 months, three-dimensionally reconstructed micro-computed tomographic images revealed better recovery of the femoral heads in OVX mice treated with TMSC-GHH. Serum osteocalcin and alkaline phosphatase were also recovered, indicating bone formation only in TMSC-GHH-treated mice, and absence in hypercalcemia or other severe macroscopic deformities showed biocompatibility of TMSC-GHH. Additionally, visceral fat reduction effects by TMSC-GHH further supported their therapeutic potential. TMSC provided therapeutic benefits toward osteoporosis only when embedded in GHH, and showed potential as a supplement or alternative to current therapies.

RNA sequencing reveals a transcriptomic portrait of human mesenchymal stem cells from bone marrow, adipose tissue, and palatine tonsils

Human mesenchymal stem cells (MSCs) are adult multipotent cells that have plasticity and inhabit the stroma of diverse tissues. The potential utility of MSCs has been heavily investigated in the fields of regenerative medicine and cell therapy. However, MSCs represent diverse populations that may depend on the tissue of origin. Thus, the ability to identify specific MSC populations has remained difficult. Using RNA sequencing, we analyzed the whole transcriptomes of bone marrow-derived MSCs (BMs), adipose tissue-derived MSCs (AMs), and tonsil-derived MSCs (TMs). We categorized highly regulated genes from these MSC groups according to functional gene ontology (GO) classification. AMs and TMs showed higher expression of genes encoding proteins that function in protein binding, growth factor, or cytokine activity in extracellular compartments than BMs. Interestingly, TM were highly enriched for genes coding extracellular, protein-binding proteins compared with AMs. Functional Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis also showed differentially enriched signaling pathways between the three MSC groups. Further, we confirmed surface antigens expressed in common and in a tissue-specific manner on BMs, AMs, and TMs by flow cytometry analysis. This study provides comprehensive characteristics of MSCs derived from different tissues to better understand their cellular and molecular biology.

Short and long-term impact of parathyroid autotransplantation on parathyroid function after total thyroidectomy

The most common complication of total thyroidectomy is parathyroid insufficiency. Acute, transient, post-operative hypoparathyroidism increases length of hospitalization, morbidity and cost associated with total thyroidectomy. While permanent hypoparathyroidism poses a significant medical burden with lifetime medication, regular follow up and considerable disease burden related to chronic renal failure and other sequelae. Parathyroid autotransplantation has been demonstrated to result in biochemically functional grafts, leading to the procedures' common use during total thyroidectomy. The clearest indications for parathyroid auto transplantation are inadvertently removed or devascularized parathyroid glands. Some centers utilize routine autotransplantation to reduce the risk of permanent hypoparathyroidism. Novel fluorescence techniques to aid in parathyroid detection during thyroid surgery are under evaluation. This review aims to define the role and impact of parathyroid autotransplantation undertaken during total thyroidectomy.

Hepatogenic Supported Differentiation of Mesenchymal Stem Cells in a Lactobionic Acid-Conjugated Thermogel

To investigate the effect of receptor substrate of target cells on stem cell differentiation, lactobionic acid-conjugated poly[(propylene glycol)-b-(ethylene glycol)-b-(propylene glycol)]-poly(l-alanine) (LB-PLX-PA) was synthesized, and then thermogelling systems consisting of LB-PLX-PA and PLX-PA in a ratio of 0/100 (LB-0), 5/95 (LB-5), and 20/80 (LB-20) were constructed as an injectable three-dimensional scaffold toward hepatogenic differentiation of tonsil-derived mesenchymal stem cells (TMSCs). Modulus of LB-0, LB-5, and LB-20 increased to 500-800 Pa at 37 °C (gel) due to the heat induced sol-to-gel transition of the systems during which TMSCs were incorporated into the gel. Based on biomarker expressions and hepatic biofunctions of the differentiated cells, the receptor substrate (LB)-conjugated bioactive thermogel provides compatible microenvironments for the differentiated cells, and thus gives pronounced positive results on the differentiation of the stem cells into target cells during three-dimensional culture, compared with a passive thermogel.

Preventive effects of tonsil-derived mesenchymal stem cells on osteoradionecrosis in a rat model

BACKGROUND

The purpose of this study was to investigate the effects of tonsil-derived mesenchymal stem cells (MSCs) on osteoradionecrosis (ORN).

METHOD

We generated a mandibular ORN rat model using a combination of 20-Gy single-dose irradiation and tooth extraction. Study groups were negative control (tooth extraction only), ORN group (irradiation, tooth extraction), Matrigel-1 group (Matrigel; BD Biosciences, San Jose, CA; irradiation, Matrigel application immediately after tooth extraction), tonsil-derived MSC-1 group (irradiation, tonsil-derived MSC application immediately after tooth extraction), Matrigel-4 group (irradiation, Matrigel application 4 weeks after tooth extraction), and tonsil-derived MSC-4 group (irradiation, tonsil-derived MSC application 4 weeks after tooth extraction).

RESULT

Bone mineral density was significantly lower in the ORN group than in the negative control group. The tonsil-derived MSC-1 group showed significantly higher bone mineral density than did the ORN and tonsil-derived MSC-4 groups.

CONCLUSION

A single 20-Gy dose of irradiation combined with tooth extraction successfully generated ORN in the rat model. The tonsil-derived MSCs can be effective for bone regeneration in ORN, particularly when applied immediately after dentoalveolar trauma or surgery.

Therapeutic potential of tonsil-derived mesenchymal stem cells in dextran sulfate sodium-induced experimental murine colitis

The therapeutic potential of tonsil-derived mesenchymal stem cells (TMSC) prepared from human tonsillar tissue has been studied in animal models for several diseases such as hepatic injury, hypoparathyroidism, diabetes and muscle dystrophy. In this study, we examined the therapeutic effects of TMSC in a dextran sulfate sodium (DSS)-induced colitis model. TMSC were injected in DSS-induced colitis mice via intraperitoneal injection twice (TMSC[x2]) or four times (TMSC[x4]). Control mice were injected with either phosphate-buffered saline or human embryonic kidney 293 cells. Body weight, stool condition and disease activity index (DAI) were examined daily. Colon length, histologic grading, and mRNA expression of pro-inflammatory cytokines, interleukin 1β (IL-1β), IL-6, IL-17 and tumor necrosis factor α, and anti-inflammatory cytokines, IL-10, IL-11 and IL-13, were also measured. Our results showed a significant improvement in survival rates and body weight gain in colitis mice injected with TMSC[x2] or TMSC[x4]. Injection with TMSC also significantly decreased DAI scores throughout the experimental period; at the end of experiment, almost complete reversal of DAI scores to normal was found in colitis mice treated with TMSC[x4]. Colon length was also significantly recovered in colitis mice treated with TMSC[x4]. However, histopathological alterations induced by DSS treatment were not apparently improved by injection with TMSC. Finally, treatment with TMSC[x4] significantly reversed the mRNA levels of IL-1β and IL-6, although expression of all pro-inflammatory cytokines tested was induced in colitis mice. Under our experimental conditions, however, no apparent alterations in the mRNA levels of all the anti-inflammatory cytokines tested were found. In conclusion, our findings demonstrate that multiple injections with TMSC produced a therapeutic effect in a mouse model of DSS-induced colitis.

Homogeneity evaluation of mesenchymal stem cells based on electrotaxis analysis

Stem cell therapy that can restore function to damaged tissue, avoid host rejection and reduce inflammation throughout body without use of immunosuppressive drugs. The established methods were used to identify and to isolate specific stem cell markers by FACS or by immunomagnetic cell separation. The procedures for distinguishing population of stem cells took a time and needed many preparations. Here we suggest an electrotaxis analysis as a new method to evaluate the homogeneity of mesenchymal stem cells which can observe the stem cell population in culture condition and wide use to various types of stem cells. Human mesenchymal stem cell, adipose derived stem cell, tonsil derived stem cell and osteogenic differentiated cells migrated toward anode but the migration speed of differentiated cells was significantly decreased versus that of stem cells. In mixture of stem cells and differentiated cells condition, we identified that the ratio of stem cell versus differentiated cell was matched with the homogeneity evaluation data of stem cells based on electrotaxis analysis. As a result, our evaluation tool has the possibility of the wide use to stem cell homogeneity evaluation and might be used as the stem cell quality control during stem cell culture without any additional antibodies.

Conditioned medium from tonsil‑derived mesenchymal stem cells promotes adiponectin production

Mesenchymal stem cells (MSCs) are often considered to be a good source for the development of regenerative medicine. Previously, we reported that tonsil‑derived MSC conditioned medium (T‑MSC CM) produces visceral fat reducing effects. As reduced visceral adiposity is closely associated with an increase in circulating adiponectin, the present study investigated the effects of T‑MSC CM on adiponectin production. T‑MSC CM was collected from previously isolated and characterized T‑MSCs and injected into senescence‑accelerated mouse prone 6 mice, which exhibit characteristics of aging and obesity. The results demonstrated a reduction in mouse weight and epididymal adipose tissue (eAT) mass following injection of T‑MSC CM. Significant increases in adiponectin expression in the eAT, and total and high molecular weight (HMW) adiponectin in the circulation were observed in the T‑MSC CM‑injected mice compared with control mice using reverse transcription‑quantitative polymerase chain reaction, western blot analysis and ELISA. In 3T3‑L1 adipocytes, T‑MSC CM treatment increased adiponectin secretion and multimerization, as detected using western blotting under non‑reducing and non‑heat‑denaturing conditions. Furthermore, glucose oxidase was used to induce oxidative stress in 3T3‑L1 adipocytes and it was observed that T‑MSC CM reduced reactive oxygen species production and the expression of certain oxidative stress markers. In addition, the results also demonstrated that the production of HMW adiponectin was increased, which indicates that T‑MSC CM may enhance adiponectin multimerization via amelioration of oxidative stress. Further studies are required to elucidate anti‑oxidant molecules secreted from T‑MSCs, and these results highlight the potential therapeutic relevance of T‑MSC CM for the treatment of obesity or obesity‑associated diseases.

Intracellular Remodeling and Accumulation of Aberrant Lysosomes in Differentiation of Tonsil-Derived Mesenchymal Stem Cells into Parathyroid-Like Cells

Differentiation of mesenchymal stem cells (MSC) into a variety of cell lineages such as adipocytes, osteocytes, and chondrocytes is often accompanied up-regulation of autophagy. In our study, we demonstrated that the expression of autophagy-associated proteins (p-Beclin 1, LC3A, LC3B, p-AMPK, p-mTOR and ATG3, ATG7, and ATG12-5) over a period of time was hardly distinguishable from control tonsil-derived MSC (TMSC). Despite the unnoticeable difference in autophagy activation between differentiated TMSC (dTMSC) and the control (cTMSC), we reported significant changes in intracellular compositions in differentiated TMSC into functional parathyroid-like cells secreting parathyroid hormone (PTH). By using transmission electron microscopy (TEM), we observed accumulation of multivesicular bodies (MVB) comprising small, degraded compartments densely accumulated as dark granular or amorphous clumps, multilamellar bodies and lipid droplets in dTMSC. However, no such structures were found in cTMSC. These results suggest that differentiation of TMSC into parathyroid-like cells producing PTH hormone is hardly dependent on autophagy activation in the beginning of our conditions. Furthermore, our results of intracellular remodeling and accumulated endo-lysosomal storage bodies in the later stages of TMSC differentiation present a possible role of the structures in PTH secretion.

The Therapeutic Efficacy of Tonsil-derived Mesenchymal Stem Cells in Dextran Sulfate Sodium-induced Acute Murine Colitis Model

Background/Aims

Mesenchymal stem cells (MSCs) are multipotent progenitor cells currently under investigation for its efficacy as the treatment for inflammatory bowel disease. In this study, we evaluated the efficacy of tonsil-derived mesenchymal stem cells (T-MSCs) as a novel source of mesenchymal stem cells and traced their localization in a murine model of acute colitis induced by dextran sulfate sodium (DSS).

Methods

C57BL/6 mice were randomly assigned to the following three groups: the normal control group, DSS colitis group (DSS+phosphate buffered saline), and T-MSC group (DSS+T-MSCs, 1×10⁶). The severity of colitis was assessed by determining the severity of symptoms of colitis, colon length, histopathologic grade, and levels of inflammatory cytokines. T-MSCs labeled with PKH26 were traced in vivo.

Results

The T-MSC group, compared with the DSS colitis group, showed a significantly lower disease activity index (11.3±1.5 vs. 8.3±1.9, p=0.015) at sacrifice and less reduction of body weight (-17.1±5.0% vs. -8.1±6.9%, p=0.049). In the T-MSC group, the histologic colitis score was significantly decreased compared with the DSS colitis group (22.6±3.8 vs. 17.0±3.4, p=0.039). IL-6 and IL-1β, the pro-inflammatory cytokines, were also significantly reduced after a treatment with T-MSCs. In vivo tracking revealed no PKH26-labelled T-MSCs in the colonic tissue of mice with acute colitis.

Conclusions

In the acute colitis model, we demonstrated that the administration of T-MSCs ameliorates inflammatory symptoms and histology. Moreover, the anti-inflammatory activities of T-MSCs were independent of gut homing.

The Use of Hydrogels as Biomimetic Materials for 3D Cell Cultures

With the recent developments in cell cultures and biomimetic materials, there is growing evidence indicating that long-established two-dimensional (2D) cell culture techniques are slowly being phased out and replaced with three-dimensional (3D) cell cultures. This is due to the 3D cell cultures better mimicking the natural extracellular matrix (ECM) where cells are found. The emergence of self-assembled hydrogels as an ECM mimic has revolutionised the field owing to their ability to closely simulate the fibrous nature of the ECM. Here, we review recent progress in using hydrogels as biomimetic materials in 3D cell cultures, particularly supramolecular peptide hydrogels. With greater comprehension of the behaviour of cells in these hydrogels, a cell culture system that can be used in a wide array of 3D culture-based applications can be developed.

Standardization of A Physiologic Hypoparathyroidism Animal Model

Ideal hypoparathyroidism animal models are a prerequisite to developing new treatment modalities for this disorder. The purpose of this study was to evaluate the feasibility of a model whereby rats were parathyroidectomized (PTX) using a fluorescent-identification method and the ideal calcium content of the diet was determined. Thirty male rats were divided into surgical sham (SHAM, n = 5) and PTX plus 0, 0.5, and 2% calcium diet groups (PTX-FC (n = 5), PTX-NC (n = 10), and PTX-HC (n = 10), respectively). Serum parathyroid hormone levels decreased to non-detectable levels in all PTX groups. All animals in the PTX—FC group died within 4 days after the operation. All animals survived when supplied calcium in the diet. However, serum calcium levels were higher in the PTX-HC than the SHAM group. The PTX-NC group demonstrated the most representative modeling of primary hypothyroidism. Serum calcium levels decreased and phosphorus levels increased, and bone volume was increased. All animals survived without further treatment and did not show nephrotoxicity including calcium deposits. These findings demonstrate that PTX animal models produced by using the fluorescent-identification method, and fed a 0.5% calcium diet, are appropriate for hypoparathyroidism treatment studies.

Tonsil-Derived Mesenchymal Stem Cells Promote Bone Mineralization and Reduce Marrow and Visceral Adiposity in a Mouse Model of Senile Osteoporosis

Osteoporosis is a disease that affects 35% women and 20% men aged more than 65 years. Reduction in bone formation and increased bone resorption are known factors that drive osteoporosis, but recent studies suggest a positive correlation between bone marrow adipose tissue (MAT) and osteoporosis. Previously, we have observed that tonsil-derived mesenchymal stem cells (T-MSCs) reduce MAT in a mouse model of bone marrow depletion. That prompted us to investigate on the senile osteoporosis to characterize the bone-forming effect, as well as MAT-reducing effect of T-MSCs. In a mouse model of senescence-accelerated mouse prone 6 (SAMP6), we injected T-MSCs or T-MSC conditioned medium (CM) through tail vein and examined changes in bone microstructure using micro-CT scan and hematoxylin & eosin (H&E) staining. Biochemical markers of osteoporosis, deoxypyridinoline (DPD) and osteocalcin, were examined by ELISA. Results demonstrated attenuation in the progression of osteoporosis, in part, by sustaining osteocalcin production and by blocking MAT accumulation. Increase in matrix mineralization was determined using in vitro culture of murine preosteoblast cell line by treatment of T-MSC CM. Interestingly, T-MSC CM induced continuous weight loss and selectively reduced visceral adipose tissue mass. Finally, antiadipogenic effects of T-MSC CM were determined in vitro. In conclusion, regulation of bone together with MAT could be considered as a new therapeutic option for the treatment of senile osteoporosis and this report may provide a framework for future cell therapy using T-MSCs.

Scaffold-free parathyroid tissue engineering using tonsil-derived mesenchymal stem cells

To restore damaged parathyroid function, parathyroid tissue engineering is the best option. Previously, we reported that differentiated tonsil-derived mesenchymal stem cells (dTMSC) restore in vivo parathyroid function, but only if they are embedded in a scaffold. Because of the limited biocompatibility of Matrigel, however, here we developed a more clinically applicable, scaffold-free parathyroid regeneration system. Scaffold-free dTMSC spheroids were engineered in concave microwell plates made of polydimethylsiloxane in control culture medium for the first 7days and differentiation medium (containing activin A and sonic hedgehog) for next 7days. The size of dTMSC spheroids showed a gradual and significant decrease up to day 5, whereafter it decreased much less. Cells in dTMSC spheroids were highly viable (>80%). They expressed high levels of intact parathyroid hormone (iPTH), the parathyroid secretory protein 1, and cell adhesion molecule, N-cadherin. Furthermore, dTMSC spheroids-implanted parathyroidectomized (PTX) rats revealed higher survival rates (50%) over a 3-month period with physiological levels of both serum iPTH (57.7-128.2pg/mL) and ionized calcium (0.70-1.15mmol/L), compared with PTX rats treated with either vehicle or undifferentiated TMSC spheroids. This is the first report of a scaffold-free, human stem cell-based parathyroid tissue engineering and represents a more clinically feasible strategy for hypoparathyroidism treatment than those requiring scaffolds.

STATEMENT OF SIGNIFICANCE

Herein, we have for the first time developed a scaffold-free parathyroid tissue spheroids using differentiated tonsil-derived mesenchymal stem cells (dTMSC) to restore in vivo parathyroid cell functions. This new strategy is effective, even for long periods (3months), and is thus likely to be more feasible in clinic for hypoparathyroidism treatment. Development of TMSC spheroids may also provide a convenient and efficient scaffold-free platform for researchers investigating conditions involving abnormal calcium homeostasis, such as osteoporosis.

Expression of tenocyte lineage-related factors from tonsil-derived mesenchymal stem cells

Human palatine tonsil-derived mesenchymal stem cells (TMSCs) are known to be a new source of progenitor cells. Using waste tissue after tonsillectomy as a cell provider can be the biggest benefit of TMSCs, compared with other stem cells. The purpose of this study was to investigate tenogenic differentiation of TMSCs and to access the differential effects of transforming growth factor beta 3 (TGF-β3) on the tenogenesis of TMSCs. Human tonsil was obtained after tonsillectomy. Using a cytometric analysis, we were able to find that the TMSCs had typical mesenchymal stem cell markers: positive for CD73, CD90, and CD105, and negative for CD14, CD34, and CD45. Using TGF-β3, the expressions of tenocyte-specific genes and proteins, such as collagen type 1 (COL1), tenomodulin (TNMD), and scleraxis (SCX), were measured by a quantitative polymerase chain reaction (PCR), immunofluorescence staining, immunohistochemistry and Western blot analyses. Quantitative PCR assay showed that TGF-β3 significantly increased the expressions of tenocyte lineage marker genes, including COL1, TNMD, and SCX, at a 3-day treatment, compared with control. However, these increases were not found at long-term exposures (7 or 10 days), except that TNMD expression was maintained at 50 ng/mL at a 7-day exposure to TGF-β3. Like genes, the protein expression levels of COL1, TNMD, and SCX were also induced in TGF-β3-treated TMSCs in a 3-day treatment, which were maintained for 10 days, as evidenced by immunofluorescence staining, immunohistochemistry and Western blot analyses. This study demonstrated that TMSCs in tenogenic stimulation with TGF-β3 have a high tenogenic differentiation potential.